SEMICONDUCTOR DEVICE, AND ELECTRIC CIRCUIT DEVICE USING SAME

PROBLEM TO BE SOLVED: To provide an UMOSFET which has a lower threshold voltage and a large saturation current. SOLUTION: In a representative embodiment of the present invention, the UMOSFET includes an n+-type SiC substrate 10 as a drain layer, an n--type SiC layer 11 contacting the drain layer as a drift layer, an p-type semiconductor layer 12 formed on the drift layer as a body layer, and an n+-type SiC layer 14 as a source layer, and has a trench groove formed from the source layer to a predetermined depth in the drift layer and a p-type electric field relaxing region 16 formed at a trench bottom portion, wherein a channel region 15 having high density than the n--type drift layer 11 and lower density than the p-type body 12 is formed from an n+-type source 13 to the p-type electric field relaxing region 16. COPYRIGHT: (C)2009,JPO&INPIT